For example, from EP-0558761B1, a linear roller bearing has become known with a guide carriage, which is supported by rollers on a guide rail by means of balls and which is provided with several endless ball channels for the balls. Each ball channel comprises a bearing channel for ball bearings, wherein these balls roll in raceways of the guide rail and the guide carriage. Each ball channel further comprises a return channel, in which the balls are returned load-free. Furthermore, the ball channel comprises two deflecting channels connecting the bearing channel to the return channel in an endless fashion. These deflecting channels are formed on end elements of the guide carriage. If the balls arranged one behind the other in the peripheral direction are designated as an endless ball chain, then this ball chain is subjected to displacement resistance in the rotational direction. This displacement resistance is traced back to friction between parts moving relative to each other or to lubricating means provided for lubricating the ball chain in the ball channel or to foreign matter in the ball channel.
Such linear roller bearings—whether those with balls or those with rollers—are often used in an environment, in which, for example, foreign matter finds its way onto the guide rail and thus also onto the guide carriage. To prevent foreign matter from finding its way into the roller body channel, linear roller bearings have been proposed, in which seals and strippers are used, which should keep the foreign matter from the guide carriage. It has been determined that such strippers and seals become damaged easily and therefore their function cannot be fulfilled perfectly. Such linear roller bearings are often installed at positions, which are accessible only with difficulty from the outside, but which, in any case, can be seen only with difficulty or even not at all. Therefore, damage to the linear roller bearings is not noticed immediately. Such damage can be caused by undesired foreign-matter deposits or else also by lack of lubrication. In the formation of pits or foreign-matter deposits, particles find their way into the roller body circuit, which increases the displacement resistance of the roller body chain.
For the case of lack of lubrication, from DE 19647939 A1 a roller bearing element has become known, in which a relubricating device is provided in order to bring lubricant into the roller body channel if needed. To monitor the relubrication, there can be sensors (pressure sensors, fluid detectors, proximity switches, or the like). However, the formation of pits or undesired foreign-matter deposits is not monitored in such linear bearing elements.